1. Field of the Invention
This invention relates to retrievable rock-climbing anchors. In particular, it is a spring-loaded reusable wedge anchor, having both finger-pressure and carabiner removal means, for insertion into crevices or drilled holes in rock faces which performs better than those taught in the prior art.
2. Description of the Related Art
The prior art shows various types of retrievable rock-climbing anchors which are used as a belay for climbers and then removed when no longer needed and saved for later reuse. Examples of patents related to the present invention are as follows, each of which is herein incorporated by reference for its supporting teachings:
U.S. Pat. No. 4,572,464 is an artificial chock stone for use by rock climbers to provide a protection point. The chock comprises a pair of slidably engaged wedges which are adjustable between a large dimension and a small dimension upon relative sliding of the wedges, which are biased to a large dimension. The device may be inserted and provide a secure protection point in a narrow, smooth-walled, paralleled-sided crevice and is constructed to provide a point of attachment to which a safety line may be secured.
U.S. Pat. No. 4,712,754 is an anchoring device for releasably anchoring within a crack in a rock face, the crack having a pair of opposed crack walls. The device has a cam member, a load cable, and expansion and retraction structure. The cam member has convexly curved cam surfaces which contact respective walls of the crack. An inner end portion of the load cable cooperates with the cam member, and an outer end portion of the cable has a loop to cooperate with a separate link or rope. An intermediate portion of the cable cooperates with shoulders of the cam member in such a manner as to rotate the cam member in first direction when the cable is pulled. This increases force acting on the crack walls and augments retention of the device within the crack. The expansion structure automatically rotates the cam member in the first direction, thus tending to initiate retention of the device within the crack. The retraction structure rotates the cam member in a second direction, opposite to the first direction, so as to decrease force on the crack walls, thus facilitating removal of the device from the crack. The invention provides a simple mechanical device which is easy to insert and remove from the crack and is particularly adapted for fitting within cracks having essentially parallel crack walls. The device is relatively insensitive to off-axis forces, which are prone to damage some prior art structures having rigid load carrying members.
U.S. Pat. No. 4,715,568 is a wedge plate with a substantially planar, rock-engaging surface and a friction surface converging with the rock-engaging surface at a non-overhauling angle to define a thick end portion of the wedge plate. A flexible tube or frame is secured to the thick end portion of the wedge plate and extends away therefrom. A body has a surface one portion of which is engageable with a rock surface and the other portion of which slidably engages the friction surface of the wedge plate. A flexible wire extends through or alongside the flexible tube or frame. The wire and tube or frame is severally connected to the wedge plate and to the body. Individual hand grips on the tube or frame and wire permit manual sliding of the wire in the tube or frame and corresponding sliding of the body and the wedge plate. A spring opposes such sliding in one direction. A climbing line connection is joined to the wire.
U.S. Pat. No. 4,834,327 discloses a self-adjusting climbing chock which includes a main cable structure having a looped end and first and second cable end sections. A fixed wedge element is joined to the cable end sections, and one of the fixed wedge element faces is provided with a tapered depression. A translating wedge element, having a bearing surface which is complementary to the sliding surface of the depression, may be manually retracted against a compression spring between a first position at which the combined thickness of the fixed and translating wedge elements exceeds the maximum thickness of the fixed wedge element and a second position in which the combined thickness does not exceed the maximum thickness of the fixed wedge element. Thus, the adjustable climbing chock may be inserted into a crevice simultaneously with finger actuation of a transverse pull component to configure the wedge end of the chock into the insertion position such that subsequent release of the transverse pull component results in the spring returning the translating wedge element to a position between the first and second positions which is variable according to the thickness of the crevice at that point. In order to obtain a chock which is capable of accommodating to irregular inner crevice surfaces, the translating wedge element is preferably a spherical section cooperating with an inside cylindrical section depression. Embodiments employing a plurality of translating wedge elements are also disclosed.
U.S. Pat. No. 5,484,132 is an expansible head safety climbing chock which has a three-part expansible head with an arcuate outer circumference and teeth extending around the circumference of both the wedge-type expansible head pieces and the inner end of a rigid body through which the safety rope or cable passes to the largest head piece. The expansible head safety chock is designed to be used in drilled holes in rock faces from which it is easily removed during non-use for aesthetic and safety reasons.
The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with a view toward discharging applicant's acknowledged duty of candor in disclosing information that may be pertinent in the examination of the application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant's claimed invention.
3. Problems with the Prior Art
In previous years, rock-climbing has become a highly popular and increasingly common sport. In it, climbers utilize safety ropes to belay them against sudden falls or to aid them in maneuvering around on a rock face. These safety ropes were historically removably attached to the rock face by pitons and/or rock bolts which were permanently attached to the rock. These fixed anchors became offensive to many outdoors enthusiasts and environmentalists due to their permanent nature and their tendency to corrode when exposed to the elements, often leaving stains on the rock which caused considerable detriment to the scenic and aesthetic worth of the rock face itself.
Such concerns prompted the move by many climbers toward the use of the "clean climb" technique, which relied upon removable and reusable climbing aids to enable climbers to scale a rock face without installing permanent attachments. These devices are used in either existing cracks in the rock or prepared orifices, and are meant to be removed when not needed.
Many of these devices have suffered from poor removability, however, thus leaving many permanently embedded in rock faces and causing the staining and degradation noted above. This is due in large part to their dependence on finger-pressure as their sole means of removal from the rock face. Thus, when the anchors become firmly embedded in the face, if finger pressure is insufficient to remove them, they must be abandoned in place, thus causing the corrosion and staining mentioned above, while also becoming an additional expense to the climber and posing a risk to anyone attempting to use them in the future.
Further, if a climber attempts to remove the anchors by force by using means other than finger-pressure, such as by attaching carabiners or other devices to the pull components to give better leverage or grip, the increased stress on the cable components of the anchors would often cause them to separate from the pull components, thus similarly leaving them permanently embedded in the rock.
In addition, many retrievable anchors are unable to provide an adequate protection point in shallow drill holes. Among the reasons for this was the long length of the anchor segment of the anchor, and the corresponding need of the anchor for sufficient depth in order to be engaged properly. Many anchors thus could not provide a safe and secure anchor point in drill holes as shallow as 1/2 inch in depth.
There is thus a need for a retrievable anchor that offers additional means to facilitate its removal from the rock when it becomes tightly wedged, which allows for the use of greater forces on the active members of the anchor while avoiding separation of the control/anchoring cables from the pull components, and which are able to provide a secure anchor point in drill holes that are shallow.